U.S. patent number 5,365,962 [Application Number 07/920,640] was granted by the patent office on 1994-11-22 for flow control system and method of operating a flow control system.
This patent grant is currently assigned to United Kingdom Atomic Energy Authority. Invention is credited to Stephen A. Taylor.
United States Patent |
5,365,962 |
Taylor |
November 22, 1994 |
Flow control system and method of operating a flow control
system
Abstract
A fluid flow control system in which a vortex valve is combined
in series with a non-fluidic control valve. The non-fluidic control
valve is upstream of the vortex valve and is so arranged that small
changes in its state control the operation of the vortex valve,
which provides the major control over the flow of the fluid.
Erosion in the non-fluidic valve due to abrasion or cavitation in
the non-fluidic valve is thereby reduced.
Inventors: |
Taylor; Stephen A. (Preston,
GB) |
Assignee: |
United Kingdom Atomic Energy
Authority (Didcot, GB)
|
Family
ID: |
10701104 |
Appl.
No.: |
07/920,640 |
Filed: |
July 28, 1992 |
Foreign Application Priority Data
|
|
|
|
|
Sep 3, 1991 [GB] |
|
|
9119196.5 |
|
Current U.S.
Class: |
137/14;
137/810 |
Current CPC
Class: |
F15C
1/16 (20130101); Y10T 137/0396 (20150401); Y10T
137/2098 (20150401) |
Current International
Class: |
F15C
1/00 (20060101); F15C 1/16 (20060101); F15C
001/16 () |
Field of
Search: |
;137/810,14,812 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Chambers; A. Michael
Attorney, Agent or Firm: Hinds; William R.
Claims
We claim:
1. A method of operating a fluid flow control system including a
vortex valve comprising a vortex chamber having an inlet for a main
fluid flow to be controlled by the vortex valve and an inlet for a
control fluid, together with a non-fluidic control valve in the
main fluid flow line upstream of the vortex valve, comprising the
operation of varying the operating state of the non-fluidic control
valve to create a difference between the pressure of fluid flowing
in the main fluid flow line and that of a control fluid in the
control flow line thereby to effect the operation of the vortex
valve to control the flow of fluid in the main fluid flow line.
2. A method as claimed in claim 1 wherein the control fluid is
taken from said main fluid flow line upstream of said non-fluidic
valve and is not separately pumped or pressurized relative to the
main fluid flow line, such that said pressure difference is
automatically effected in dependence on the state of said
non-fluidic valve.
3. A fluid flow control system including a vortex valve comprising
a vortex chamber having an inlet for a main fluid flow to be
controlled by the vortex valve and an inlet for a control fluid,
wherein there is included a non-fluidic control valve in the main
fluid flow line upstream of the vortex valve, and including means
for using differences between the fluid pressures in the main and
control fluid flow lines arising from changes in the state of the
non-fluidic control valve to control the action of the vortex
valve.
4. A fluid flow control system according to claim 3 wherein the
control fluid is derived directly from the main fluid flow line
upstream of the non-fluidic control valve so that initially the
main and control fluids are at substantially the same pressure.
5. A fluid flow control system as claimed in claim 4 wherein the
control fluid flow line is devoid of separate pumping or
pressurizing means relative to the main fluid flow line.
6. A fluid flow control system comprising a cylindrical vortex
chamber adapted to form part of a main fluid flow line and having
an inlet and an axial outlet, a plurality of tangential inlet ports
situated at the downstream end of the cylindrical chamber for a
control fluid, a non-fluidic control valve situated in the main
fluid flow line upstream of the inlet to the cylindrical vortex
chamber, a control fluid flow line connecting the main fluid flow
line upstream of the non-fluidic control valve to the control
ports, and means for varying the state of the non-fluidic control
valve thereby to create a difference between the fluid pressure in
the main fluid flow line at the inlet to the vortex chamber and
that in the control fluid flow line thereby to effect the operation
of the vortex valve.
7. A fluid flow control system as claimed in claim 6 wherein the
control fluid flow line is devoid of separate pumping or
pressurizing means relative to the main fluid flow line.
Description
AN IMPROVED FLOW CONTROL SYSTEM
The present invention concerns fluid flow control systems.
A major problem with industrial fluid flow systems, particularly
when a fluid is abrasive, such as a slurry or aerosol, or contains
dissolved gases, is erosion of control valves included in the fluid
flow systems, due either to the abrasive nature of the fluid
itself, or to cavitation when the valves are operating in a state
in which they present considerable resistance to the flow of the
fluid.
It is an object of the present invention to provide a fluid flow
control system and method of operating a fluid flow control system
in which the erosion of control valves is reduced.
Generally according to the present invention a fluid flow control
system includes a vortex valve comprising a vortex chamber having
an inlet for a main fluid flow to be controlled by the vortex valve
and an inlet for a control fluid, a non-fluidic control valve in
the main fluid flow line upstream of the vortex valve, and means
for using differences between the fluid pressures in the main and
control fluid flow lines arising from changes in the state of the
non-fluidic control valve to control the action of the vortex
valve.
Also generally in accordance with the invention, a method of
operating a fluid flow control system including a vortex valve
comprising a vortex chamber having an inlet for a main fluid flow
to be controlled by the vortex valve and an inlet for a control
fluid, together with a non-fluidic control valve in the main fluid
flow line upstream of the vortex valve, comprises the operation of
varying the operating state of the non-fluidic control valve to
create a difference between the pressure of fluid flowing in the
main fluid flow line and that of a control fluid in the control
flow line thereby to effect the operation of the vortex valve to
control the flow of fluid in the main fluid flow line.
The non-fluidic valve can be any form of mechanical valve, such as
for example a tap, butterfly or diaphragm and can be operated
manually or by power means.
The invention will be described further, by way of example, with
reference to the accompanying diagrammatic drawings, in which:
FIG. 1 is a diagrammatic sketch of a flow control system;
FIG. 2 is an embodiment of the flow control system; and
FIG. 3 illustrates a component part of a vortex valve.
The drawing shows a vortex valve 1 included in a flow line 2 for a
fluid which can be gas or liquid. The vortex valve is a fluidic
device having a vortex chamber 3 with inlet, outlet and control
ports. In the present arrangement fluid flowing along the flow line
2 in the direction indicated by the arrow enters radially into the
vortex chamber 3 at the inlet port and emerges axially from the
chamber 3 at the outlet port.
A further flow line 4 is connected to the control port or ports of
the vortex valve 1 and extends to a junction 5 in the first flow
line 2 upstream of the vortex valve 1. A non-fluidic valve 6 is
included in the flow line 2 at a position between the junction 5
and the vortex valve 1. The valve 6 can be any suitable type of
mechanical valve and as example only mention can be made of
butterfly and diaphragm valves. In addition the valve 6 can be
operated by hand or by power means. The further flow line 4 can
itself form or can include a flow restrictor to provide required
divisions of flow between the lines 2 and 4.
In use and with the valve 6 fully open fluid in the line 2 can flow
unhindered through both the valve 6 and the vortex valve 1. In the
absence of control flow the vortex valve is in its low resistance
mode.
Upon closing the valve 6, a pressure difference is created across
the valve 6 with the result that the pressure at the inlet to the
vortex valve 1 is less than the pressure at the upstream side of
the valve 6 and hence is less than the pressure in the further flow
line 4 to the control port. Thus, closing the valve 6 causes an
increase in the pressure difference between the control and inlet
ports. The control flow along the further flow line 4 acts on the
flow along the line 2 to create a vortex in the vortex chamber 3 to
thereby increase the flow resistance of the vortex valve 1. The
resistance of the vortex valve 1 increases progressively with the
closing of the valve 6.
The combination of the valve 6 and the vortex valve 1 functions as
a control in the flow line 2. A small pressure drop across the
valve 6 resulting in a small control flow can cause a significant
increase in the resistance of the vortex valve 1 to flow along the
line 2. The advantage from this arrangement compared to a
non-fluidic valve alone in the flow line 2 is that the main
resistance to flow occurs in the vortex valve 1 and does not take
place at the valve 6. As mentioned a slight closing of the valve 6
can effect a considerable increase in the flow resistance of the
vortex valve 1. Upon closing the valve 6 the flow velocity
therethrough increases with consequent problems of erosion and
cavitation effects on the valve 6. In combination with the vortex
valve it is not necessary to close the valve 6 to the same extent
as when using the valve 6 alone to obtain the same control in the
flow. As a result the problems of erosion and cavitation are
reduced with improved life for the valve 6.
FIGS. 2 and 3 show one embodiment of the system and where
applicable the same reference numerals are used in FIG. 2 to denote
the corresponding components in FIG. 1.
In FIG. 2, the vortex valve 1 and the non-fluidic valve 6 are
mounted or secured to flanges 7 at the ends of a short length of
pipe 8, the pipe being a part of the flow line 2. In this
embodiment the valve 6 is a butterfly valve.
The vortex valve 1 comprises a body 9 centrally supported within an
annular body 10 by a spider 11. The body 10 is secured to the
flange 7 at the end of the pipe 8. An annular plate 12 is mounted
on the body 10 and the valve 1 is completed by a cover housing 13
secured to the plate 12. An outlet diffuser 14, being a part of the
flow line 2, extends axially from the cover housing 13.
A vortex chamber 15 is formed between the body 9 and the annular
body 10 and the plate 12. The body 9 comprises a cylindrical
portion with a conical portion directed towards the valve 6.
A conduit 16 provides communication between apertures in the
flanges 7. A passage 17 in the housing of the valve 6 extends from
the conduit 16 to open into the flow line 2 immediately upstream of
the butterfly valve 6, the flow direction being shown by the arrow
in FIG. 2. A similar passage 18 in the annular body 10 provides
communication between the conduit 16 and a continuous circular
groove 19 formed in the face of the annular body 10 abutting
against the annular plate 12.
As shown in FIG. 3, the annular plate 12 is formed with four
equiangularly spaced apart channels or slots 20, each slot 20
having a nozzle 21 communicating substantially tangentially with
the bore of plate 12.
The path formed by the passage 17, the conduit 16, passage 18,
groove 19, slots 20 and nozzles 21 corresponds to the flow line 4
in FIG. 1.
* * * * *